Precast concrete curb and gutter with interlocking joint



March 23, 1965 c. J. BOYD ETAL PREcAsT CONCRETE CURB AND GUTTER WITH INTERLOCKING JOINT Filed July 19, 1961 8%@ e mz ATTORNEYS Patented Mar. 23, 1965 3,174,412 PRECAST CONCRETE CURB AND GUTTER WITH INTERLOCKING JINT Curtis J. Boyd, S25 S. 3rd St., and Charles H. King, Jr., 604 Hillside Drive, beth of lJIayeld, Ky. Filed July 19, 1961, Ser. No. 125,156 7 Claims. (Cl. 94-31) This invention relates to precast concrete units for a combined curb and gutter system for roadways, and in particular to a unit having improved interlocking features. All curbing is subject to various conditions and forces which tend to rupture and dislocate the masonry, and misaligned or otherwise abnormal curbing is of common occurrence. Among the causes may be mentioned periodically varying ground water conditions, or inherently yielding subsoil, freezing and thawing, vibrations due to heavy traffic, and heavy, direct impacts by vehicles. In order to compensate for expansion and contraction, and also provide a flexibility enabling the curbing to adjust to varying ground conditions along lits length, the curbing is made in separate, abutting sections of length. In the case of a curbing cast in place, it is impractical to provide an interlocking feature, and the observed, tilted, sunk or upraised curb sections are a consequence of this shortcoming.

Various proposals for prefabricated curb sections with interlocking features have been proposed, but none have attained any noticeable degree of acceptance, for reasons which would seem to be related to failure of the interlocking features to measure up to the demands presented by the breakdown conditions in curbing systems.

It is therefore a general object of the present invention to provide an improved interlocking arrangement for prefabricated curb sections.

More particularly, it is an object to provide interlocking which is universally effective to prevent separation of the curbing, in movement of translation longitudinally and laterally of the curbing, in movement upward and downward, and in twisting movement about the longitudinal extent of the curbing.

A related object is to provide a universal interlocking feature as aforesaid, in which the strength features are distributed in respect to the dislocation forces in the several directions mentioned.

Another, and important object of the invention is to provide combined curb and gutter sections, in which the interlocking feature is predominantly associated with the gutter portion.

Other objects include providing a curb section which is possessed of high strength throughout, is easily handled, readily slipped into interlocking engagement, and which presents minimized difiiculties with respect to foreign matter in the regions of interlock.

-These and other ends, which will be apparent, are attained by the present invention, as described in the following specification, and illustrated in the drawing, in which:

FIGURE 1 is a'top plan view of one complete section of the curb-gutter combination;

FIGURE 2 is a front elevational view of the section shown in FIGURE l;

FIGURE 3 is an end elevational view of the section shown in FIGURE 2, as seen from the right of that ligure, and showing the male joint element;

FIGURE 4 is an end elevational view of the section shown in FIGURE 2, as seen from the left of that figure, and showing the female joint element;

FIGURE 5 is a sectional view through an interlocked pair of mating couplers, taken on a line shown at 5-5 in FIGURE 3, and in FIGURE 4;

FIGURE 6 is a perspective, fragmentary view, showing the end of the curb-gutter section having the male coupler; and

FIGURE 7 is a fragmentary view, similar to FIGURE 2, showing a modified bottom.

Referring to the drawing by characters of reference, the concrete masonry unit comprises a curb portion 10, of generally sector-form cross section, with a vertical rear wall or face 12, such that the curb is roughly quarterround in shape. On the street side, the unit has a vertical face 14, parallel to face 12, and the gutter section of the unit comprises a slab, extending between face 14 and the curb 1G, and having a generally planar, upper surface 16. The curb and gutter have a common, planar, bottom surface 1S, perpendicular to faces 12 and 14, and upper surface 16 has a gentle slope downward, between face 14, and a cove corner 20 at the bottom of the curb, which slope conforms with the crown of the road.

The complementary, interlocking elements are situated on the respective ends of the unit just described. The male element 24, shown to good advantage in FIGURE 6, is best described in relation to a vertical end face 22 of the curb-gutter unit, proper, which face is perpendicular to the three surfaces 12, 14 and 18. This male element, which is of about half the cross-sectional area of the unit proper, extends in the longitudinal direction from face 22, and has a bottom surface 26, coplanar with bottom surface 18 of the unit. The outer 4face 28 of the element is perpendicular to bottom 26, and joins with a top surface 30, which terminates short of end face 22 of the unit, being separated therefrom by a laterally extending channel recess, having a sloping side wall 32 which connects with top surface 30, a bottom 34, parallel to bottom 26, extending to end face 22 of the unit, which latter constitutes the other side wall of the channel. The male element has downwardly diverging side walls 36, 3S, so that, as viewed endwise, it has the form of a dovetail joint element. The element 24 is centrally located with respect to the end face 22 of the unit, and on each side of the element, the face 22 has a pair of recessed surfaces 40, 42 parallel to end face 22, and connected thereto by sloping surfaces 44, 46. At the lower end of surfaces 40, 42, the corner of the unit is bevelled, to provide slant faces 4S, 50, slanted in the same general sense as faces 44, 46.

Except for the bevelled corners 48, 50, the female ele ment, on the other end of the unit, is complementary in all respects to the male element. The surfaces in the latter are all designated by even numbers, and the associated surfaces in the female element will be designated, in each case, by the odd numeral succeeding the even numeral. Thus, slant sides 37, 39 mate with sides 36, 38, respectively, surface 3S dwells on the channel bottom 34, and the bottom 31 of a well, beyond surface 35,

wells on surface 30. Also, main end surface 23 abuts surface 22, and projections 52, 54, have end faces 41, 43, abutting surfaces 40, 42, and bevelled faces 45, 47, which mate with slant surfaces 44, 46. It will be noted that faces 41, 43 extend to the bottom 26 of the unit, and do not mate with slant surfaces 48, Si). This leaves a clearance between adjacent units to accommodate debris dislodged from the joint in the coupling operation.

Strictly speaking the respective end units are not entirely male and female, since the female includes pro truding parts 52, 54, and the depending surface 35. However, the respective parts are predominantly male and female, and in so treating them in the specification and claims, it is to be understood to be in the interest of clarity and simplification, and that minor departures are nevertheless involved.

The concrete unit is reinforced by suitable steel bars, two such, 56, 58, being employed in the modification illustrated. ln order to guard against all major stresses which may be expected to be encountered, the bars or rods extend longitudinally of the unit, and are substantially coextensive in length therewith, and extend into the male clement. In order to take care of bending stresses, as during hoisting, the rods are preferably located near the bottom of the unit, being bent inward in the region of the interlocking elements. Thus, at the female end, the rods are bent inward, as at 60, followed by a short,

longitudinally extending section 62, and a downwardlyturned, end hook 64, to conform to the hook shape of the female element. Likewise, at the male end. the rods have an upward bend, as at 66, a longitudinal section 68, and an upturned end hook 70, conforming with the hook shape of the male element. For handling, the concrete unit is provided. on the street side, and on the opposite side, with a pair of rectangular recesses 72, arranged at an angle` in upwardly divcrging relationship designed lo receive the grappling hooks of a hoisting sling. The angular disposition of the recesses presents optimum strength opposing the stresses imparted during hoisting.

it will be seen that the interlocking parts are easily brought into engagement, by bringing a female end over a male end, and lowering. During lowering movement, a slant surface 33 in the well of the female provides a camming action along slant surface 32 of the male, which slides the new section into abutment with the previously laid section, such that surface 23 contacts surface 22, and extensions 52, 54 move into the side niches of the male clement. The seating by a camming action may, of course, be assisted by a force applied longitudinally of the unit being laid. The important consideration is that by virtue of the compound features of the interlocking arrangement, the parts are brought inevitably into true position of alignment, without the need for tools or instruments, or the attention of operators with special skill. ln particular, the several slant surfaces enable the parts to be quickly brought into final. accurate position, after only a very rough spotting of the part being laid. lt will be understood, of course, that according to usual practice. an expansion pad of bituminous or other matcrial will be inserted between the abutting end faces, as by trowcling, for instance.

lt will also be noted that the cross section of the systcm, in the region of the joint, is fairly evenly divided between the male and female elements, which provides maximum strength in the same sense as a chain with all links of equal strength. Furthermore the sum total of the respective parts of the joint is equivalent to the cross section ofthe main body of the unit. ln the distribution of the loads, surfaces 22, 28, 40 and 42 take thc end thrust of the unit in one direction, and slant surface 32 in the other direction; surfaces 30, 32 and 34 take the downward vertical load, with surfaces 44, 46 resisting upward movement; slant surfaces 36, 38 assume both vertical and lateral loads. Besides its load-carrying and locking functions. slant surface 32 also serves to ease the parts into interlocking engagement.

With the parts interconnected, the system is not only locked against separation, longitudinally and laterally, and also against twisting action in both a horizontal and vertical plane, but is locked by a system wherein the parts are so arranged that the resisting strength is fairly well distributed to counteract, in satisfactory degree, the respective forces tending to cause the types of dislocation enumerated. Also of importance is the fact that the main interfaces of the joint are substantially within the region of the gutter portion, so that overturning forces and the like. on the curb are but little manifest in the joint.

ln the modification shown ln FIGURE 7, the bottom of the unit is provided with transversely extending corrugations 74, which lessen the need for n carefully prepared bed, and also assist in anchoring the unit.

While a certain, preferred, main embodiment has been shown and described, various modifications will become apparent, in the light of this disclosure, and the invention should not, therefore, be deemed as limited, except insofar as shall appear from the spirit and scope of the appended claims.

We claim:

l. A prefabricated unit for roadways, comprising a curb portion rising from a gutter portion, and complementary male and female coupling elements on the respective ends of said unit, said male elements comprising a reduced extension located in the lower part of said unit, inwardly of the sides thereof, and having an upwardly hooked, outer end, said unit having n transverse recess on each side of said extension, said unit having a well in its under side, on the female end, complementary to said extension on the male end, and -a pair of projections adapted to be received in the recesses of the male end.

2. A device as in claim l, said hooked end having a slanted, inner face.

3. A device as in claim l, said extension being dovetailed in lateral profile.

4. A device as in claim l, said extension being dovetailed in lateral profile, and said hooked end having a slanted inner face.

5. A prefabricated unit of combined gutter and curbing. comprising -a curb portion rising from a gutter portion, and complementary male and female coupling elements on the respective ends of said unit, said male element comprising a reduced extension of dovctail protile, laterally, located in the lower part of said unit, inwardly of the sides thereof, and having an upwardly extending outer end, with a slanted. inner face, said unit having transverse recesses on each side of said extension, with bevelled, upper corners, said unit having a well in its underside on the female end, adapted to receive said upwardly extending end of the male element, and an end notch communicating with said well and mating with said extension of the male clement inwardly of said upwardly extending end thereof, said well having slant walls complcmentary to the dovctail profile of said extension and a slant wall complementary to said slanted, inner face of said upwardly extending end, and a pair of extensions on the female end of said unit, having slant, upper edges, and receivable in said recesses in the male end of said unit.

6. A prefabricated unit of combined gutter and curb ing, comprising a curb portion, rising from a gutter por tion. and complementary male and female coupling clemcnts on the respective ends of said unit, said male element comprising a reduced extension, centrally of the cross section of said unit, and prcponderantly within the region of said gutter portion, with a bottom copianar witr said unit and a top located medially of said bottom anc' the top surface of said gutter portion, said extension hav ing a transverse channel with one wall coinciding will the end face of said unit, and the opposite wall incliner in a positive, oblique angle to said end face, said ex tension having downwardly diverging side walls denni a dovetaii profile, said end face having a transverse reces on each side of said extension with upper and lowe corners bevelled, said female clement comprising a pai of legs with slant, inner surfaces complementary to sait diverging side walls in the male section, and extendin forwardly of the end face of said unit for reception i the respective, said recesses at the male end, and havin slant upper edges cooperating with the upper, bevelle edges of said recesses, said female element having a cro: member extendingv between said legs, defining a we adapted to receive said top of said extension in the ma element, and having a slant, inner face, complementar to the inclined wall of said channel, whereby said cro member is adapted to mate with said channel.

7. A prefabricatcd unit of combined gutter and cur ing, comprising a curb portion, generally quarter rout in cross section rising from a slab-like gutter portion, at complementary male and female coupling elements t the respective ends of said unit, said male element cor prising a reduced extension, centrally of the cross sectit of said unit, and preponderantly within the region of said gutter portion, with a bottom coplanar with said unit and a top located medially of said bottom and the top surface of said gutter portion, said extension having a transverse channel with one wall coinciding with the end face of said unit, and the opposite wall inclined in a positive, oblique angle to said end face, said extension having downwardly diverging side walls dening ya dovetail prole, said end face having a transverse recess on each side of said extension with upper and lower corners bevelled, said female element comprising a pair of legs with slant, inner surfaces complementary to said dverging side walls in the male section, `and extending forwardly of the end face of said unit for reception in the respective, said recesses at the male end, and having slant upper edges cooperating with the upper, bevelled edges of said re- References Cited by the Examiner UNITED STATES PATENTS 696,792 4/02 Bedell 94-31 746,399 12/03 Staples 50-450 1,166,664 1/16 Dargento 94-31 1,176,611 3/16 Smith 94-31 1,707,574 4/29 Rothmann 94-3 1 3,077,703 2/ 63 Bergstrom 50-346 JACOB L. NACKENOFF, Primary Examiner. 

1. A PREFABRICATED UNIT FOR ROADWAYS, COMPRISING A CURB PORTION RISING FROM A GUTTER PORTION, AND COMPLEMENTARY MALE AND FEMALE COUPLING ELEMENTS ON THE RESPECTIVE ENDS OF SAID UNIT, SAID MALE ELEMENTS COMPRISING A REDUCED EXTENSION LOCATED IN THE LOWER PART OF SAID UNIT, INWARDLY OF THE SIDE THEREOF, AND HAVING AN UPWARDLY HOOKED, OUTER END, SAID UNIT HAVING A TRANSVERSE RECESS ON EACH SIDE OF SAID EXTENSION, SAID UNIT HAVING A WELL IN ITS UNDER SIDE, ON THE FEMALE END, COMPLEMENTARY TO SAID EXTENSION ON THE MALE END, AND A PAIR OF PROJECTIONS ADAPTED TO BE RECEIVED IN THE RECESSES OF THE MALE END. 